package string;
/** StringBuilderDemo */
public class StringBuilderDemo {
    public static void main(String[] args) {
        String str  ="好好学习Java";
        //复制str的内容到builder中---好好学习Java
        StringBuilder builder = new StringBuilder(str);

        //append():追加内容---在末尾追加
        builder.append(",为了找个好工作");
        System.out.println(builder);//好好学习Java,为了找个好工作

        //replace():替换部分内容(含头不含尾)
        builder.replace(9,16,"就是为了改变这个世界");
        System.out.println(builder);//好好学习Java,就是为了改变这个世界

        //delete():删除部分内容(含头不含尾)
        builder.delete(0,8);//删除下标为0到7的
        System.out.println(builder);//,就是为了改变这个世界

        //insert():插入内容
        builder.insert(0,"活着");
        System.out.println(builder);//活着,就是为了改变这个世界



        /*
        //StringBuilder的创建方式
        StringBuilder builder1 = new StringBuilder();//空字符串
        StringBuilder builder2 = new StringBuilder("abc123"+"45");//abc串
        //String和StringBuilder互转
        String str = "abc";
        StringBuilder builder3 = new StringBuilder(str);//abc串
        String str2 = builder3.toString();
        System.out.println(builder2);
         */
    }
}
